Tribiphenylmethane dyestuff and pigment dyestuffs and process for making the same



Patented Sept. 7, 1948 1 UNITED STATES PATENT OFFICE TRIBIPHENYLMETHANEDXESTUFF PIGMENT DYESTUFFS AND PROCESS,

FOR MAKING SAME AlcxanderrHt Ropkin, Bronx, N. Y., assignorato SunChemical Corporation, a corporation. of

Delaware.

D wina Ap i ati Match-1 19 4;

Serial No. 526,131 -9;Qlai n s. (61. 2 60193817). 1 2 Th1s:inventionrelates to coloring materials Another-object'ofxthe inventionisztofapreparez from reacted products of biphenyl, and more hithertounknown triarylmethane pigmeniudslea P l rly to tri'biphenylmethanedyestuffs and studs-by effectingreaction:betweemanzoxidation pigmentdyestufis, and toy methods for produce product of substituted:derivatives:.otihiphenyic Such-materials. and an acidsuchassphosphotungstic acidephose:

It is ;;an: object of' the invention to provide prod phomolybdicacidgphosphotungstomoly dic acid?! ucts .dyestufis and pigment dyestuffshitherto andtannic acid. unknown-,xby treatment of biphenyl and certainOtherobjects oftheszinventiorr wiilzbetappanat f; the reac diproduc sthereof: ent from the followingidescriptionxandiappendadi.

Another; object of the invention is to prepare 10 claims;hitherto-unknown; triarylmethane dyestuffs by I have foundaccordingto'the presenttimtene effectingloxidation of. certainsubstituted derivation that when biphenyl, or certain of thhtfi tivesprepared by "nitration .andzreduction of Ibiaetedcproductsthereofltaisatreated lander; reaction Dconditionsas:hereinafter:describedsfthat-xa series-"- Another-object theinvention is 1iolfilmis'h '15tor-hitherto:unlenownzcoloringvagents,areazsecuredzit suchprodllcts:which may generally hewrepresuch'coloringragents comprisingbothadyestufisii sented .ibytthfi fo and pigment l dyestufls; have adistinctive saviqletie blue-shade.

T Several. illustrative?examplesxare;'hereinaitei r zo'given.of"=the-products or -the; invention and: processes .for securingsuchaproducts, represem tative of successful-practical: operations.

Examples-1 .-,-In.: a: reaction-wesselqare: placede 4 moles not:biphenyl; 356: cc: of:sulfuric;acid :(sn: gr. 1.849 3-16v cc:-ofinitric-iacidz :(sp.:--gr: 11.42)? Land: 2281 cc: tof' wate-r:Subsequently"tthereaaiswincQF-' porated' ithereint-a :mixture O'fi'f243cc; of tsulfiirici acid "(sprgn 1.84") and 512 cc. of nitric acid: :(spngr. 1.42) under conditions -suchxthat-tpnedqmia 'nant1y- Z-nitrobiphenylrand i4i1-nitrobiphenyltare! formed, and. satisfactory;resultsareisecured' 'witlrr the materials above t describecvby keepingr-the.mixture underinterereactive agitation; as l t. stirring; throughout theaddition period, 'byteaddin which X represents a monovalent, divalent,or 5 ing the mixture of nitric and sulfuric-yaeidsaslovw trivalentanion, and n is 1, 2, or 3. 1y over-a period of,approximatelyvtwoihoucs;vby

Another object of thefiinvention is to furnish maintaining agitation for:La pB 0 PPr0xi-- such' products which may "generally berepremately fourhours after addition of the acids is S8I1tBd7bY r-thezfor-mula:completed to insure completion oi.t,he,;mononi- 40. tration reaction,and by keeping thetcqntentstgt.

-410" (3. as heating throughout the additiqn; and.. subsequent reactionperiod At. the end of the reaction period described above, the acidmixture is withdrawn as by decantation, and the remaining materialwashed several times-with waterxzandudilute sodiumaoafibonate solutionsto remove; the .1 acid- -.-remaining=.w

The! washed product "then is dried as iby. meeting;

to approximately 100-; inxthisrway :a' mixture:

of 2T-nitrobiphenylw and .4.-znitrobiphenyl is see cured; 4

To separate z-nitrobiphenyl, the mixedsprodanot is heated-untilcompletely imeltem and than permitted tow crystallize: rwithoutx-stirring; The-a the reaction vessel at a temperature of about,

crystals thus secured are removed, as by centrifuging, and the oil fromwhich the crystals have been separated distilled to separate2-nitrobiphenyl, which is recovered from the distillate. 3, x

Easample 2.A solution of 100 grams of 2-nitrobiphenyl (satisfactorilyprepared as described in Example 1) in 50 cc. of benzene is added to avaddition of water, which, with the quantities above described takesabout four hours, the contents of the reaction vessel are maintainedunder reflux, as by heating, and under effectivereduction admixtureconditions as by agitation. v

The reaction mixture subsequently is treated as .by centrifuging toremove the iron borings. The benzene solution then is separated from thewater layer, suitably by decantation, and admixed with 200 cc. of 3N.hydrochloric acid to effect-formation of a precipitate of2-aminobiphenyl hydrochloride. The latter is separated as by filtration,and treated with a base, such as caustic soda, to effect formation of2-aminobiphenyl.

Examplei-A mixture of 67 gms. o-aminobiphenyl (satisfactorily preparedas described in Example 2) 74 gms. methanol and '7 gins. sulfuric acid(66 B.) is placed in an autoclave and heated under reactive methylatingconditions, and with the quantities above described, satisfactoryconditions are secured when the materials are heated for approximately 4hours'at temperatures in the range 200-210 C., and under pressures ofabout 400-500 lbs. per square inch. At the end of the reaction period,the reaction mixture is made alkaline=as with an aqueous solution ofsodium carbonate. The alkaline mixture then is extracted with benzeneand the benzene extract allowed to evaporate to facilitate removal ofbenzene. When benzene has been evaporated, the residue is satisfactorilydistilled under reduced pressure, and'the portion distilling at 144 to146.'5 C. at 10 mm. pressure of-mercury collected as the desiredproduct. This fraction is essentially o-phenyl-N,N-dimethylaniline, witha relatively minor proportion of o-phenyl-N- methylaniline.

Toeffect oxidation of said product, a mixture is prepared, consistingof:

. Grams Sodium chloride 175 Copper sulfate 10 Phenol, a Water v 2o-Phenyl-N,N-dimethylaniline 32.6

4 action product, and appears as a separate layer, which is removed fromthe other materials present as by decantation. A yield of approximatelyof a salt of the oxidation product of o-phenyl-N,N-dimethylanilinetheoretically 0btainable from the above series of reactions thusissecured.

' The salt of the oxidation product of o-phenyl- N,N-dimethylanilineprepared as described is treated to effect formation of a free dye base,satisfactorily with an aqueous solution of sodium hydroxide.

The free dye base is such that when treated with an aqueous solution ofan acid such as hydrochloric, a solution of triarylmethane dyestufi ofviolet-blue color is secured, applicable for coloring of cotton, wooland silk.

Also, the free dye base prepared as described alternately may bedissolved in oleic acid to give a solution of dye. Suchviolet-bluesolutions are eiiective as a toning or coloring agent in compositionssuch as paints and printing inks, and coating compositions, for example.

For utilization as a coloring agent in a coating composition, forexample, a pigment dyestufi which is insoluble in the vehicle can beprepared according to the present invention. And in practice, successfulcommercial operations have been secured by preparing materials such as a'tungstated, tungstomolybdated, molydated or tannated pigment dyestufifrom the dyestuifs above described. As an illustrative example of thepreparation of one such material, 3.3 parts of sodium tungstate, 21.78parts of sodium molybdate, 2.98 parts of sodium monohydrogen phosphateand 9.6 parts of concentrated sulfuric acid are dissolved in 500 partsof water, the acidity of the solution then being adjusted to pH 3. Thetemperature of the solution is maintained at approximately roomtemperature and parts of an aqueous solution containing 10 parts of thefree dye base above described and 5 parts of hy drochloric acid addedunder conditions such that effective reaction admixture is secured, andsuch conditions are obtained with the above quantities by agitation, asby stirring of the admixture during the addition period. When theaqueous solution of free dye base has been incorporated, the temperatureof the mixture is raised to about 60 C., as by heating to complete thecolor development of the pigment dyestuff, and the latter then separatedfrom the remaining materials, as by flltration. The separated pigmentdyestuff is washed with water to remove water-soluble materials, andthen dried as by warming to removewater. A pigment dyestuff is obtainedwhich has a clean, strong, blue color.

The new dyestufls and pigment dyestuffs prepared by practicing thisinvention are of distincl tive color characteristics as described. Theycan be employed as direct coloring agents for cotton, wool, silk, astoning agents and pigments for coating compositions. Further, it is seenthat applicants new dyestuffs and pigment dyestuffs retain theirdistinctive color characteristics when employed in the forms describedand can be utilized in practical application where such dyestufls andpigment dyestufis are applicable,

In preparation of a solution of dyestufi by treatment of the free dyebase with an aqueous solution of an acid as above describedhydrochloricacid, which is an aqueous solution of hydrogen chloride, generally isemployed because of its availability and cost. Successful results havebeen secured with other water-soluble acids such tion of dyestuffsolutions according to theipresent invention, these acids furnishingmonovalent,

divalent or trivalent anions in aqueous solution.

While one method of preparinga pigment dye-=1 stuff by interaction ofthe oxidation product of o-phenyl-N,N-dimethylaniline has beendescribed, other acids forming pigment dyestuffs, as tannic acid, may beemployed. The acids, typified by phosphotungstic acid, phosphomolybdicacid, phosphotungstomolybdic acid, and tannic acid comprise a group ofacids which may be employed in preparing pigment dyestuffs fromsolutions of soluble dyestuffs.

Because of the complexity of the physical and chemical structure of suchpigment dyestufis, it is not possible to state with certainty the for--mulas of these materials. However, it is known that the dye basecombines with the particular acid or acids chosen so as to form aninsoluble coloring material which may be a simple compound or a mixtureof compounds, and which has the color properties described. One possibleway in which the structure of these materials may be represented is bythe general formula:

CH3 I where Y represents an anion of the phosphotungstic acid,phosphomolybdic acid, phosphotungstomolybdic acid, or tannic acid groupand p and r are small integers. r I

But whatever the structureof such materials,

it is certain that when the dyebasesoi thepresent invention are reactedunder efiective reac tion admixture conditions as described, that avariety of insoluble pigment dyestuffs of distinctive color and utilityare secured.

The term dyestuff as used in describing applicants invention is intendedto designate a coloring agent which is soluble in the vehicle in whichit is employed. The term pigment dyestuffs is intended to mean aninsoluble salt of a dyestufi'. By the term toning agent is meant acoloring agent which generally is utilized to impart a desired shade ofcolor to a pigmented composition. Thus, for example, in printing inkcontaining gas black pigments such as carbon black or mixtures of gasblack pigments with other black pigments, a relatively small proportionof a coloring agent often is employed to impart a desired shade to theblack printing ink.

While the products herein described and the methods of producing thesame constitute preferred embodiments of the invention, it is to beunderstood that the invention is not limited to these precise productsand methods, and that changes may be made therein Without departing fromthe scope of the invention which is defined in the appended claims.

What is claimed is:

1. A water-soluble tribiphenylmethane dyestuff represented bythe-formula:

in which X represents an anion and his 1,2, or 3. 2. A fattyacid-soluble tribiphenylmethane dyestuff represented by the formula:

3. A coloring agent represented by. the formula:

ing said oxidation product in an aqueous acid medium.

6. The process of preparing a triarylmethane pigment dyestuff whichcomprises effecting oxidation of o-phenyl-N,N-dimethylaniline underacidic conditions in the presence of a mixture of sodium chloride andcopper sulfate, thereafter separating the oxidation product, thereafterdissolving said oxidation product in an aqueous acid medium and reactingsaid dissolved oxidation product with an acid forming an insolublepigment therewith, and thereafter separating and recovering theprecipitated product.

7. A pigment dyestuff represented by the formula:

Q 0113/ /CHs C: =N Y1 CH:

D CH where Y represents an anion of a water soluble acid, and where pand r are small whole numbers.

8. A pigment dyestuff represented by the formula:

where Y represents an anion of a water-soluble phosphotungstomolybdicacid, and where p and r are small whole numbers.

9. A water-soluble tribiphenylmethane dyestuff represented by theformula:

ALEXANDER H. POPKIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Barnett, Coal Tar Dyes and Intermediates, pp. -121(1919).

Hickinbottom, Jour. of the Chem. Soc. (London) 1932, pp. 2646 to 2649.

Morton et a1., Jour. of the American Chemical Society, vol. 61, pages2902 to 2905 (1939),

